1 /* 2 * linux/ipc/msgutil.c 3 * Copyright (C) 1999, 2004 Manfred Spraul 4 * 5 * This file is released under GNU General Public Licence version 2 or 6 * (at your option) any later version. 7 * 8 * See the file COPYING for more details. 9 */ 10 11 #include <linux/spinlock.h> 12 #include <linux/init.h> 13 #include <linux/security.h> 14 #include <linux/slab.h> 15 #include <linux/ipc.h> 16 #include <linux/msg.h> 17 #include <linux/ipc_namespace.h> 18 #include <linux/utsname.h> 19 #include <linux/proc_ns.h> 20 #include <linux/uaccess.h> 21 22 #include "util.h" 23 24 DEFINE_SPINLOCK(mq_lock); 25 26 /* 27 * The next 2 defines are here bc this is the only file 28 * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE 29 * and not CONFIG_IPC_NS. 30 */ 31 struct ipc_namespace init_ipc_ns = { 32 .count = ATOMIC_INIT(1), 33 .user_ns = &init_user_ns, 34 .ns.inum = PROC_IPC_INIT_INO, 35 #ifdef CONFIG_IPC_NS 36 .ns.ops = &ipcns_operations, 37 #endif 38 }; 39 40 atomic_t nr_ipc_ns = ATOMIC_INIT(1); 41 42 struct msg_msgseg { 43 struct msg_msgseg *next; 44 /* the next part of the message follows immediately */ 45 }; 46 47 #define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg)) 48 #define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg)) 49 50 51 static struct msg_msg *alloc_msg(size_t len) 52 { 53 struct msg_msg *msg; 54 struct msg_msgseg **pseg; 55 size_t alen; 56 57 alen = min(len, DATALEN_MSG); 58 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL); 59 if (msg == NULL) 60 return NULL; 61 62 msg->next = NULL; 63 msg->security = NULL; 64 65 len -= alen; 66 pseg = &msg->next; 67 while (len > 0) { 68 struct msg_msgseg *seg; 69 alen = min(len, DATALEN_SEG); 70 seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL); 71 if (seg == NULL) 72 goto out_err; 73 *pseg = seg; 74 seg->next = NULL; 75 pseg = &seg->next; 76 len -= alen; 77 } 78 79 return msg; 80 81 out_err: 82 free_msg(msg); 83 return NULL; 84 } 85 86 struct msg_msg *load_msg(const void __user *src, size_t len) 87 { 88 struct msg_msg *msg; 89 struct msg_msgseg *seg; 90 int err = -EFAULT; 91 size_t alen; 92 93 msg = alloc_msg(len); 94 if (msg == NULL) 95 return ERR_PTR(-ENOMEM); 96 97 alen = min(len, DATALEN_MSG); 98 if (copy_from_user(msg + 1, src, alen)) 99 goto out_err; 100 101 for (seg = msg->next; seg != NULL; seg = seg->next) { 102 len -= alen; 103 src = (char __user *)src + alen; 104 alen = min(len, DATALEN_SEG); 105 if (copy_from_user(seg + 1, src, alen)) 106 goto out_err; 107 } 108 109 err = security_msg_msg_alloc(msg); 110 if (err) 111 goto out_err; 112 113 return msg; 114 115 out_err: 116 free_msg(msg); 117 return ERR_PTR(err); 118 } 119 #ifdef CONFIG_CHECKPOINT_RESTORE 120 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 121 { 122 struct msg_msgseg *dst_pseg, *src_pseg; 123 size_t len = src->m_ts; 124 size_t alen; 125 126 if (src->m_ts > dst->m_ts) 127 return ERR_PTR(-EINVAL); 128 129 alen = min(len, DATALEN_MSG); 130 memcpy(dst + 1, src + 1, alen); 131 132 for (dst_pseg = dst->next, src_pseg = src->next; 133 src_pseg != NULL; 134 dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) { 135 136 len -= alen; 137 alen = min(len, DATALEN_SEG); 138 memcpy(dst_pseg + 1, src_pseg + 1, alen); 139 } 140 141 dst->m_type = src->m_type; 142 dst->m_ts = src->m_ts; 143 144 return dst; 145 } 146 #else 147 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 148 { 149 return ERR_PTR(-ENOSYS); 150 } 151 #endif 152 int store_msg(void __user *dest, struct msg_msg *msg, size_t len) 153 { 154 size_t alen; 155 struct msg_msgseg *seg; 156 157 alen = min(len, DATALEN_MSG); 158 if (copy_to_user(dest, msg + 1, alen)) 159 return -1; 160 161 for (seg = msg->next; seg != NULL; seg = seg->next) { 162 len -= alen; 163 dest = (char __user *)dest + alen; 164 alen = min(len, DATALEN_SEG); 165 if (copy_to_user(dest, seg + 1, alen)) 166 return -1; 167 } 168 return 0; 169 } 170 171 void free_msg(struct msg_msg *msg) 172 { 173 struct msg_msgseg *seg; 174 175 security_msg_msg_free(msg); 176 177 seg = msg->next; 178 kfree(msg); 179 while (seg != NULL) { 180 struct msg_msgseg *tmp = seg->next; 181 kfree(seg); 182 seg = tmp; 183 } 184 } 185